A fairness cup, also known as a equality cup (Gongdao Bei), is essentially the same as what is commonly called a tea pitcher or tea fair cup. Simply put, its purpose is to hold brewed tea to prevent the leaves from steeping for too long, which can cause bitterness and astringency. It is also used for evaluating and balancing the flavor of the tea.
When brewing tea, it is inevitable that you might not finish drinking it right away. If the leaves are left to steep continuously in the teapot, the tea liquor will become too concentrated, resulting in bitterness and astringency. To keep the tea liquor at its ideal, sweetest state, it needs to be poured out into a separate vessel as soon as it is done brewing. This is why the fairness cup was created.
Not only does the fairness cup prevent the tea from steeping for too long, but it also helps balance the strength of the brew. If different steepings taste too strong or too weak, they can be blended together to achieve the most consistent and pleasant flavor. This is also how the fairness cup and equality cup got their names.
Common materials include glass, porcelain, and Yixing clay. Tea lovers who brew frequently may want to get one, as it can enhance the joy and quality of your tea experience. If you prefer not to buy one, you can also use a bowl from home or another larger teacup as a substitute to achieve the exact same effect.